Piston for hydraulic pumps.



R. ESNAULVPELTEWE. WSTON FR HYDRAULIC PUMPS. APPLICATION mw oc.'12',1911.

Patented J an. 29, w18.

ROBERT ESNAULT-PELTERIE F PARIS, FRANCE.

rs'roN Fon HYDRAULIC PUMPS.

Application led October 12,

To all whom, it may concern.'

Be it known that l, Roimrrr lsNAuL'r-luL- rnnIE, a citizen of the Republic ot' France, residing at 1l Rue de Milan, Paris. Seine. in the Republic of France, have invented certain new and useful Improvementsin Pistons for Hydraulic Pumps, of which the following is a specification.

The present invention relates to an improved piston-for a high pressure hydraulic pump.

In a hydraulic pump producing considerable power, the pressure. attains auch a value that the diameter oi' the piston is too small to receive the lower end of the connecting rod internally and in consequence one is led to make use of a piston crosshead ot' much larger dimensions than the pistou itself, inside which it will be feasible to lodge the lowerend of the rtnuiccting rod,

Even under these conditions it is not permissible to allow the piston to have any play inv its packing, since it'. is necessary to ohviate leakage, on the contrary it is necessary for the cross head to have a certain amount of play in its guide7 since it must not seize.

lt follows from this necessity of giving" the cross-head some play that when the piston and cross-head are at'the beginningr of their power stroke, the thrust of cross-head connecting rod or pitman is such that the cross-head becomes, by wear, slightly eccentric with respect to the pump cylinder, and there results a lateral stress on the piston packing prejudicial to the preservation thereof and capable of becoming so excessive as to seize. This would occur even in the case, not realizable in. practice, in which the bore of the pump cylinder and that of the cross-head guide are rigorously concentric.

The object .of the present invention is to obviate this disadvantage.

To this end the crosshead a instead of receiving the lower )art of the piston Z dircctly carries a ro c, which enters the said Specification of Letters Patent.

Patented Jan. 29, 1918.

1917. serial No. 196,314.

yhollow piston with clearance (Z slightly .greater than clearance e of the crosshead o in its guide f, the said rod c being connected te the said piston only at its upper extremity'.

It is quite obvious, that in consequence of the slight transverse flexibility of the rod c inv question, the piston b has the power al ways to remain centered in its packing g,-

notwithstanding the clearance c which the crosshead o must necessarily have 1n its guide ln the accompanying drawing, the clearances al and e have been intentionally 91mg-,

geratcd to facilitate comprehension. The piston illustrated is of the plunger type, 'but it goes without saying that the present invention is identically applicable to any other type of piston.

What is claimed .is-

l. A high pressure pump comprising a piston and a cross-head, said cross-head having a width relatively great as regards the diameter ot' the piston', said piston having greater transverse freedom with respect to the cross-head than the transverse clearance of said cross-head to its guide.

2. A high pressure pump according to claim l, said piston having a recess in its' underside and said cross head having a rod thereon connected to said piston Within said recess, said rod having the clearance in said recess necessary to allow said greater transverse freedom of the piston with respect to the cross-head.

3. A high pressure pump according to claim 1, said cross-head having a rod thereon connected to said piston, said rod having thelearance necessary to allow said eater transverse freedom of the piston vvlth` re-V spect to the cross-heini.`

In testimony whereof I alix in presence of two witnesses.

ROBERT ESNAUL'I `-PELTERIE. iVitnesses: *,HAs. P. PREssLY,

HENRI CARTIER.

my signature sof 

